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The early Eocene Sakesar Limestone of the Salt Range has been investigated in detail for microfacies analysis, depositional modeling, diagenesis and reservoir characterization. This research work was comprised of two outcrop sections, i.e., Nilawahan Gorge Section (NGS) and Katas Temple Sections (KTS) of the Sakesar Limestone, central and eastern Salt Range, Potwar Plateau. This work is mainly concentrated on investigating and evaluating the reservoir quality through depositional and diagenetic fabrics. The depositional, diagenetic and deformational processes are controlling factors of porosity and permeability distribution. On the basis of relative estimated ratio of allochemical constituents and micrite, five microfacies have been recognized. These microfacies are: Benthonic Foraminiferal wackestone, Foraminiferal-Algal wackestone–packstone, Miliolidal-Algal wackestone–packstone, Nummulitic-Assilina Packstone and Alveolina-Algal packstone. On the basis of relative abundance of biota, their associations and the presence of micritic matrix in various microfacies, the Sakesar Limestone is interpreted to be deposited in the proximal inner ramp to middle ramp settings. The Sakesar Limestone is largely affected and modified by various diagenetic events which have destroyed primary nature of reservoir and developed it as prolific secondary reservoir. The paragenetic sequence includes micritization, cementation, dissolution, neomorphism, nodularity, silicification, mechanical compaction, stylolitization, fractures and veins formation. The identified porosity types include intraparticle, intercrystalline, moldic, cavernous and fracture. The visually estimated average micro porosities of the Sakesar Limestone vary between 0.5 and 2.1% in the NGS and KTS. The core plug porosity and permeability of outcrop samples vary between 0.9 and 2.9%. The relation of core plug porosity and permeability has moderate positive correlation coefficient. The fractures and dissolution on microscopic and macroscopic level are the dominant factors that enhance the reservoir potentiality of the Sakesar Limestone.

The Salt Range, in Pakistan, preserves an insightful sedimentary record of passive margin dynamics along the NW margin of the Indian Plate during the Mesozoic. This study develops provenance analyses of the Upper Triassic (Kingriali Formation) to Lower Jurassic (Datta Formation) siliciclastics from the Salt and Trans Indus ranges based on outcrop analysis, petrography, bulk sediment elemental geochemistry, and heavy-mineral data. The sandstones are texturally and compositionally mature quartz arenites and the conglomerates are quartz rich oligomictic conglomerates. Geochemical proxies support sediment derivation from acidic sources and deposition under a passive margin setting. The transparent heavy mineral suite consists of zircon, tourmaline, and rutile (ZTR) with minor staurolite in the Triassic strata that diminishes in the Jurassic strata. Together, these data indicate that the sediments were supplied by erosion of the older siliciclastics of the eastern Salt Range and adjoining areas of the Indian Plate. The proportion of recycled component exceeds the previous literature estimates for direct sediment derivation from the Indian Shield. A possible increase in detritus supply from the Salt Range itself indicates notably different conditions of sediment generation, during the Triassic–Jurassic transition. The present results suggest that, during the Triassic–Jurassic transition in the Salt Range, direct sediment supply from the Indian Shield was probably reduced and the Triassic and older siliciclastics were exhumed on an elevated passive margin and reworked by a locally established fluvio-deltaic system. The sediment transport had a north-northwestward trend parallel to the northwestern Tethyan margin of the Indian Plate and normal to its opening axis. During the Late Triassic, hot and arid hot-house palaeoclimate prevailed in the area that gave way to a hot and humid greenhouse palaeoclimate across the Triassic–Jurassic Boundary. Sedimentological similarity between the Salt Range succession and the Neo-Tethyan succession exposed to the east on the northern Indian passive Neo-Tethyan margin suggests a possible westward extension of this margin.

A detailed lithostratigraphic, bulk organic geochemical and palynofacies analyses were performed on organic-rich shale and coal samples from the Hettangian Datta Formation in the western Salt Range, southern Potwar Basin, Pakistan, to evaluate its hydrocarbon generation potential. Organic matter (OM) in the formation is mainly dominated by gas-prone Type III kerogen and oil- and gas-prone Type II kerogen. The coal and OM-rich shale intervals are thermally mature, while grey shale intervals are thermally immature. Palynofacies studies showed that the Datta Formation is rich in inertinite, vitrinite and amorphinite with minor liptinite. The OM is mainly of terrigenous origin with minor marine contribution and is interpreted to have been deposited under suboxic to anoxic conditions in a fluvio-deltaic depositional setting. The thermal maturity estimated from Spore Colour Index (SCI) and Thermal Alteration Index (TAI) was entirely consistent with estimates based on bulk organic geochemical data. Variations in thermal maturity are interpreted to be due to change in kerogen types as well as burial depth. Overall, the organic geochemical and palynofacies studies showed that the coal and OM-rich shale intervals in the Datta Formation have good-to-excellent source rock potential in the study area, whereas the grey shale intervals have poor potential as source rocks. The Datta Formation has tentatively been correlated with the stratigraphically equivalent Lathi Formation in the Jaisalmer Basin, India, which was deposited in a similar palaeo-depositional setting on the NW margin of the Indian Plate affected by Neo-Tethys realms. Research Highlights Organic matter within the Datta Formation is dominated by Type III and Type II kerogens. The Lower Jurassic Datta Formation is enriched in inertinite, vitrinite and amorphinite with minor liptinite. The Datta Formation was deposited in a fluvio-deltaic setting influenced by both terrigenous and marine organic influx. The suboxic to anoxic conditions during shales deposition promoted organic matter preservation. Datta Formation correlates with the Lathi Formation of Jaisalmer Basin of India.

The Cretaceous pelagic carbonate succession, i.e., Goru Formation was studied in the Chutair Section, Sulaiman Range, representing part of the eastern Tethys for the paleoenvironment and bio-sequence stratigraphy. Eight planktonic foraminiferal biozones are identified which include: 1. Muricohedbergella planispira Interval Zone; 2. Ticinella primula Interval Zone; 3. Biticinella breggiensis Interval Zone; 4. Rotalipora appenninica Interval Zone; 5. Rotalipora cushmani Total Range Zone; 6. Whiteinella archeocretacea Partial Range Zone; 7. Helvetoglobotruncana helvetica Total Range Zone; and 8. Marginotruncana sigali Partial Range Zone representing Albian-Turonian age. The petrographic studies revealed five microfacies: 1. Radiolarians-rich wacke-packestone microfacies; 2. Radiolarians-rich wackestone microfacies; 3. Planktonic foraminiferal wacke-packestone microfacies; 4. Planktonic foraminiferal wackestone microfacies; and 5. Planktonic foraminiferal packestone microfacies; indicating deposition of the Goru Formation in outer-ramp to deep basinal settings. Based on the facies variations and planktonic foraminiferal biozones, the 2nd and 3rd order cycles are identified, which further include six transgressive and five regressive system tracts. The sea level curve of the Goru Formation showed fluctuation between outer-ramp and deep-basin, showing the overall transgression in the 2nd order cycle in the study area, which coincides with Global Sea Level Curve; however, the 3rd order cycle represents the local tectonic control during deposition of the strata.

An integrated approach was deployed to relate the petrographical and petrophysical parameters of the Chorgali Formation to assess its reservoir potential. The petrographical study of the Chorgali Formation, exposed in Khair-e-Murat Range, disclosed that the original texture and composition are affected by diagenetic events (i.e. micritization, dolomitization, microfractures, stylolitization, compaction, dissolution, neomorphism and cementation). Of these, dissolution, dolomitization and microfractures enhanced reservoir quality, while micritization, compaction, neomorphism and cementation reduced reservoir suitability. Micritization occurred in marine phreatic conditions; dolomitization existed in the marine-meteoric mixing environment; dissolution, neomorphism and cementation took place in meteoric conditions. The mechanical and chemical compaction occurred in a burial diagenetic environment. In addition, the relationship among formation resistivity factor ( F ), compressional wave velocity ( V p ) and porosity ( ɸ ) was also validated for the Eocene Chorgali Formation of Meyal Oil Field, Potwar Plateau, Pakistan. There is an inverse relationship between ɸ and F , V p , however, the relation between F and V p is directly proportional. Such inter-relationships assist in determining and interpreting the geological processes based on petrophysical parameters ( ɸ , F and V p ). F and V p may be high due to cementation, compaction, sealed fractures and lack of deformation in carbonates. On the other hand, F and V p may be low due to dissolution, dolomitization, vacant fractures, lack of compaction and cementation. Similarly, ɸ is enhanced by processes lowering F and V p and reduced by processes increasing F and V p . Hence the diagenetic processes enhancing and reducing the porosity influence the electric and elastic properties of the carbonate rocks.

This paper comprises of two sections. The first section describes challenges in the Carboniferous–Permian Gondwanan stratigraphic palynology, and progress in techniques such as presence of the ‘rare-marine intervals’, and ‘radiometric dating’ in some Gondwanan successions, e.g., South Africa, Australia and South America, as tools to confidently calibrate these palynozones. The second section describes developments in the palynological work on the Carboniferous–Permian Nilawahan Group of the Salt Range, Pakistan, and summarises their correlation with the coeval succession of the Gondwana continents and with the Russian/International stages.

An integrated approach has been deployed to investigate dolomite of the Eocene Chorgali Formation exposed in the Khair-e-Murat Range, Potwar Plateau, Pakistan. Two typical genetic dolomite groups are identified and interpreted based on X-rays Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS), chemical alizarin red staining and petrographic studies. The first group is represented by early-diagenetic alizarin-red-unstained dolomites. They are associated with evaporite(s) (gypsum) and characterized by stoichiometric composition of 50.28 mole % CaCO3 and degree of order is 0.682. The second group includes fine crystalline, alizarin-red-unstained relatively early late or late diagenetic dolomite crystals not associated with evaporite(s). It is represented by nearly stoichiometric composition of 48.76 mole % CaCO3 and degree of order varies from 0.58 to 0.9747. The dolomite associated with evaporite (gypsum) is interpreted to be precipitated in arid peritidal (sabkha) environment while the other dolomite not associated with evaporite is reflecting dolomitization in open diagenetic system (mixed marine-meteoric environment). Within the Chorgali Formation, the presence of dolomite is enhancing the reservoir capability making it prospective for hydrocarbon exploration. The photomicrographs based estimated porosity values are 2.0 % and 1.0% for dolomite associated with evaporite(s) and dolomite-not- associated with evaporite(s) respectively, however, qualitative permeability seems to be relatively higher in dolomite associated with evaporite(s).

[...]of compaction, volume reduction and pore-water expulsion take place within the sediments. The green carbonaceous clay facies of maximum flooding surface acts as permeability barrier, resulting in the reservoir compartmentalization within the Chichali Formation to act as trapping/sealing horizons. [...]these glauconitic sands bounded by shale facies might serve as potential reservoirs in the sub-surface. On average, the maximum regression associated arenites in the middle unit of the Lumshiwal Formation may act as good reservoirs in the subsurface while the transgression associated lower and uppermost units may act as permeability barriers and may form prolific stratigraphic traps in the subsurface and adjoining sedimentary basins, i.e. northwestern part of the Potwar and Kohat basins. 7.Conclusions * The Chichali Formation in the Nizampur Basin, Pakistan consists of laterite, glauconitic sandstone and carbonaceous green shales lithofacies, representing transgression associated deposition in the middle to outer ramp depositional setting. * The intergranular pores filling materials include calcite, hematite, smectite, ferroan dolomite and glauconitic cement in the Chichali Formation, thereby reducing the porosity of the formation. Dolomitization, intergranular and dissolutions porosity have resulted in increase in the porosity within glauconitic sandstone lithofacies of the Chichali Formation. * The Lumshiwal Formation consists of bioclastic sandy limestone, sandy carbonaceous shale, white quatrzose sandstone, glauconitic sandstone, interbedded thin bedded bioclastic limestone and marls facies. * On the basis of vertical succession and depositional environments, the deposition of Lumshiwal Formation took place during three depositional cycles; cycles 1-3. * The lowermost cycle resulted the deposition of mixed carbonates and silicastic sequence with six regressions TRT 1-6 and five regressions (i.e. RST 1-5). * The cycle 2, is responsible for the deposition of intertidal sequence of quartz arenite and clay facies. * The uppermost cycle 3 is represented by lower sandy limestone unit and upper monotonous sequence of the bioclastic limestone and marls. * The middle depositional cycle 2 deposited during maximum regression may act as good reservoir with the overlying cycle 3 acting as permeability barrier.

The Lower Jurassic Datta Formation, western Salt Range, Pakistan, comprises three facies associations: (1) channel belt facies association (CBFA), (2) channel margin, and overbank facies association (CMOFA), and (3) lagoonal facies association (LFA). A cyclic fining-upward trend in the succession is represented by basal quartzose conglomerate/pebbly sandstone, through coarse to fine quartzose sandstone to siltstone and shales/claystone, which contains some carbonate accumulation. Two prominent depositional sequences are recognized in the Datta Formation with the lower high and upper low magnitude cycles. The Datta Formation thus represents a thick sedimentary succession and in the study area, i.e., western Salt Range, mainly channel belt, flood plain and/or delta top facies are exposed. The palaeocurrent analysis shows that the source area with acidic plutonic rocks laid to S–SE in the Indian shield, aravalies or older sedimentary rocks of the Indus Basin (i.e., Khewra, Tobra and Warchha formations). A tentative stratigraphic correlation of the Datta Formation with the lower Jurassic Lathi Formation, India invites further work in parts of India, which will elaborate the extent of the Datta Formation in the Greater Indian peninsula and develop palaeogeographic setting for this Lower Jurassic deltaic rock unit.

Over the last five decades the Karakoram Glaciers has revealed irregular behavior and lack of stability. These anomalies lead surge of glaciers and the formation of glacier lakes, and now risk increasing in the context of climate change. The hazard associated with glacier lake outburst floods (GLOFs) has become an increasingly serious threat to the life, property, livelihoods and infrastructure in the Karakoram Mountains of Pakistan. Shishper Glacier Lake in the Shishper watershed areas of central Hunza in North Pakistan, after its latest activity has turned to a highly prone GLOF hazard. Shishper Glacier and Glacier Lake in the North Pakistan can be harmful to the downstream population and have large socioeconomic impacts if an outburst occurs. This study investigated the spatio-temporal changes in Shishper glacier and its glacial lake, and associated risk of potential GLOF hazard. Shishper glacier was assessed on the basis of field survey carried out in December 2018 combine with GIS and remote sensing data for morphometric, land cover change, physical vulnerability and temporal analysis of Shishper glacier. The Glacier has shown an anomalous behavior in the month of July 2018, no prominent lake was observed while in the month of November 2018 a lake with an area of 0.026 km2 was noticed. Similarly, in the month January, 2019 a prominent lake appeared with an area of 0.057 km2. The physical vulnerability results showed that 80% of the area of Hassanabad village is highly exposed to GLOFs hazard, whereas low lying areas along the Hunza River are also susceptible to inundation. The results show that there is immediate danger of catastrophic outburst through downward movement of the glacier. The study recommends the glacier has an anomalous behavior, it is necessary to monitor the glacier and Glacier Lake continuously, and minimize the adverse effects of potential GLOFs risk. We also recommend strong understanding the phenomenon of glaciers therefore, glacier lakes are very important in north Pakistan with respect to GLOF disaster management.